Automatic fuse plug



June 13, 1939. N. DIPPEL 2,162,163

AUTOMATIC FUSE PLUG Filed July 27, 1937 2 Sheets-Sheet l NICHOLAS Dwpa. Z3 INVENTOR ATTORNEY:

June 13, 1939. I N, DWEL 2,162,163

AUTOMATIC FUSE PLUG Filed July 27, 1957 2 Sheets-Sheet 2 Fry. 6 Fry. 7 F1 8 'IIIIIIIIIII 1 9 f 1 1 f 1 1 1 i 1 i 9 1 1 f I 1 1 1 1 1 i i 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 l 1 1 1 1 1 1 1 i 1 NICHOLAS DIPPEL INVENTOR ATTORNEVb Patented June 13, 1939 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to improvements in replaceable fuses and more particularly to improvements in fuses of this type wherein a plurality of fuse elements are automatically placed in circuit when one is destroyed by a surge of current.

Heretofore in this art the fuses employed have contained only one fuse element so that when the fuse is blown the entire plug must be removed and a new one inserted. Among the disadvantages of this type of element can be mentioned the necessity of ascertaining the blown fuse plug and replacing same before current can again pass through the circuit, and also the cost of replacing said fuse plugs.

It is the main object of the present invention to provide a type of fuse plug containing a plurality of fuse elements disposed therein and provided with means so that when one of said elements is destroyed by means including an overload or surge in current, certain of the other fuse elements will be placed in the circuit thereby preventing disruption of service and in efiect provide means for automatically replacing blown fuses. An advantage of this type of structure over that heretofore known lies in the fact that it provides a means whereby blown fuses are automatically replaced by new fuses without necessitating the service or attendance of an operator. Accordingly, blow-outs in isolated places need not, when employing the present invention, result in disruption of service.

A further feature of the present invention is that it permits the construction of novel fuse plugs of the character indicated without substantially increasing the cost of manufacturing over that of old types.

The invention will be fully and comprehensively understood from a consideration of the following detailed description when read in connection with the accompanying drawings which form part of the application.

Figure 1 is a top plan view partially in section of a screw fuse plug prepared in accordance with the present invention showing the fuse elements disposed in their normal relationship,

Figure 2 is a top plan view partially in section of a screw plug prepared in accordance with the invention illustrating the fuse plug disposed in the relationship assumed after one element has been destroyed,

Figure 3 is a vertical sectional view taken along the line 3-3 of Figure 1,

Figure 4 is a side view partially in section of the structure shown in Figure 1 illustrating certain details of its construction,

Figure 5 is an exploded perspective view of certain elements of the fuse structure illustrated in Figure 1,

Figure 6 is a vertical plan view of a cartridge type fuse embodying the present invention,

Figure 7 is substantially a vertical side view of the matter shown in Figure 6,

Figure 8 is a section of Figure 7 taken along the line 8-8,

Figure 9 is a section of Figure 7 taken along the line 99,

Figure 10 is a partial section of the operating portion of the fuse element shown in Figure 6 with one of the elements destroyed, and

Figure 11 is an exploded view of certain of the elements shown in Figure 6.

Referring to the drawings, Figures 1 to 5 illustrate one embodiment of the present invention wherein a screw plug type of fuse is adapted to automatic replacement in the event of a blow-out. The fuse comprises a casing member I5 formed of electrical insulative material carrying the metallic threaded member generally designated at It adapted to engage with the threads in the fuse plug socket, and the central contact member IT. The terminals of the fuse comprise the members l6 and I! which are connected to the fuse elements by metallic members passing through the casing. The member I6 is held in place upon the casing element by means including the threaded screw element generally designated at l8 comprising an upper head portion slotted to facilitate turning by a screw-driver and the lower threaded portion adapted to engagement with a nut and passing through a lug formed integral with the member l6, substantially as shown in Figure 4. The screw I1 engages with a pierced threaded portion of the L-shaped member l9 which is disposed within the casing of the fuse substantially as shown, the upper part of the member being held in position by a screw 20 passing through a hole therein and engaged with the casing.

The upper portion of the element l9 carries a U-shaped member having piercings therein adapted to provide a mounting for the rocker arm 2| so that a pin. positioned within holes in rocker arm and. U-shaped member permits said rocker arm to substantially freely move about its pivot. The rocker arm is formed at one end substantially as shown at 22 in Figure 5 whereby a fuse element 23 can be positioned within the prongs of the fork and held in substantially fixed position forming electrical contact therewith. The other end of the fuse element 23 en- Gil gages with a corresponding fork member 24 of the element 25 which is mounted by means of the screw 18 upon the casing member l5. Accordingly a complete electrical circuit is provided between the terminals of the fuse plugs l6 and I! through the fuse element 23.

An auxiliary fuse element 26, held in position between a forked end 21 of the element 25 and another forked element 28 mounted in the casing by the screw 29, is provided in the event that the fuse 23 is destroyel by an over-load of current. This fuse element 26 is normally out of circuit with the fuse terminals I6 and I! and is placed in circuit only when the rocker arm 2| is moved in a clockwise direction by the spring 30 which is mounted upon the pivot supporting the rocker arm in the U-shaped portion of the element l9. Clockwise movement of the arm 2| is normally prevented by tension in the fuse element 23, but when this element is destroyed the tension is relieved and accordingly the rocker arm 2! moves as hereinabove mentioned, thereby establishing contact between the end of said rocker arm and the fork member 28, completing the circuit between the terminals !6 and H through the fuse element 26.

In the preferred embodiment of the present invention as relates to plug type fuses it is desirable that the fuse be covered by a slip jacket 3| adapted to snap engagement with the casing l5 and having a substantially transparent window 32 whereby the user can detect a blow-out in the main fuse. It is also preferred, though not an essential part of the present invention, that a portion of the casing member 15 be slotted as indicated at 33, said slot being formed of a depth and width adapted to receive the ends of fuse blanks whereby they may be bent to fit into the fork members aforementioned.

In operation this fuse is inserted in a line in substantially the same manner as an ordinary plug type fuse. When a surge occurs in the line whereby the current drawn exceeds the capacity of the fuse, the fuse element normally in circuit is destroyed and the rocker arm snaps over establishing contact with the auxiliary fuse element. In this manner the circuit is substantially uninterrupted by a destruction of the fuse due to momentary surges and accordingly it is unnecessary for an operator to be continually in attendance upon the fuse box in those types of equipment wherein continuity of service is of major importance. This meritorious feature of the present invention is likewise of importance in the usual house lighting circuits inasmuch as automatic substitution of a new fuse for the blown fuse permits the user to replace the fuse in the line at such time as it is convenient to interrupt the service instead of necessitating im mediate replacement as has been heretofore the case.

Figures 6 to 11 inclusive illustrate an application of the present invention to cartridge type fuses. The terminals of fuses of this type comprise metallic heads positioned on the ends of electrical insulative cylinders, the fuse element usually being disposed within said insulative cylinder and attached to the metallic caps thereof. In this embodiment of the present invention an electrical insulative cylinder 50 is provided at one end with a cap-shaped member 5| having a standard 52 formed integral therewith and disposed coaxially within said cap and drilled and tapped in an upper portion thereof substantially as shown in Figure 6. The electrical conductive member 53 carries .a projection adapted to engage with the threaded portion of the standard 52 and is positioned thereon with the washer 54 carrying the clips 55 disposed substantially as shown. The upper portion of the element 53 is forked and pierced whereby an insulating element 56 can be substantially fixedly positioned therein as illustrated. The sides of the element 56 are adapted to engage in slots in the insulative casing 59 whereby rotative movement of said element 56 relative to said casing is substantially prevented.

The member 60, formed substantially as shown in Figure 11, is held in relatively fixed position by a forked element formed thereon, as indicated at 59, upon the upper end of the insulative member 56, and held by a set screw substantially as shown in Fig. 6. The upper portion of the element 60 is threaded and adapted to be secured within the cap member 6| forming the other terminal of the fuse. A pair of pierced uprights 62 are disposed upon a portion of the member 60 substantially as shown in Figure 11 and are adapted to receive a pivot whereby the rocker element generally designated at 63, can be supported in movable position thereon. A portion of the element E0 generally designated at 65 is extended to form a support for an insulative body generally designated at 65 which is fixedly positioned thereon and carries a spring clip 51. The auxiliary fuse element 68 is positioned substantially as shown in Figure 6 and held in relatively fixed position under the clips 55 and El. The fuse element 69 is held under the clip 55 and the other end is disposed beneath the spring clip 10 which is positioned upon the projection H and the rocker arm 63 and is normally held under tension by the spring 12 which is mounted upon the pivot supporting said rocker arm in the U elements and which abuts against a portion thereof substantially as shown in Figure 10. Accordingly the circuit between the members 5i and GI is normally completed through the fuse element 59 substantially as described, but in the event that the fuse element 69 is destroyed by a momentary surge of current passing through same, the spring 12 throws the rocker arm 13 in a counter-clockwise direction thereby establishing contact between the portion 15 of said rocker arm and the clip 61 whereby the circuit between the terminals 5! and BI is completed through the fuse element 68.

It is preferred that a portion of the upper face of the member 60 be slotted substantially as indicated at H whereby the ends of fuse elements can be bent to adapt them to fit under the spring clip element as indicated.

It is a notable feature in the present invention that the fuse devices so prepared in addition to permitting continuity of service even when one fuse is destroyed, permits the operator to use much less expensive means of replacing fuses than is now the case by permitting him to utilize ordinary fuse blanks instead of necessitating the replacement of the entire plug or cartridge.

It is to be understood that this improvement is capable of extended application and is not confined to the exact showing of the drawings nor to the precise construction described, and therefore, such changes and modifications may be made therein as do not affect the spirit of the invention nor exceed the scope thereof as expressed in the appended claims.

I claim:

1. A device of the type described comprising an electrically insulative casing member, a plurality of electrically isolated terminals mounted on said casing, a plurality of electrically conductive strip elements, bent at the ends, physically alterable in a predetermined manner by known variations in electrical circuits wherein said elements are included, bifurcated supporting members engaging with bent end portions of said elements for holding same within the casing; means for connecting certain of said elements in series with said terminals without so connecting other of said elements, and means solely actuatable by aforementioned physical change in elements so connected whereby the elements not theretofore connected in the electrical circuit are made a part thereof and substituted for the altered elements.

2. In a screw type fuse plug of the type described, comprising a plurality of electrical conductive strip elements having bent end portions and characterized by being destroyed by certain predetermined electrical conditions, bifurcated supporting members receiving and engaging with said bent end portions of said strip elements for holding same, means for establishing an electrical circuit wherein certain of said elements are included, means whereby said certain elements are automatically replaced in electrical relationship in said circuit when destroyed by conditions aforementioned, by other elements not previously forming a portion of said electrical circuit, and means whereby the changes aforesaid are visibly displayed.

3. In a cartridge type fuse of the type described including a casing, and electrical terminals mounted thereon, a plurality of electrical conductive strip elements having bent end portions, physically alterable in a predetermined manner by known variations in electrical circuits wherein said elements are included, bifurcated springpressed supporting members adapted to receive and engage with said bent end portions of said strip elements for holding same, means for connecting certain of said elements in series with said terminals without so connecting another portion of said elements, and means solely actuatable by aforementioned physical change in elements so connected whereby the elements not theretofore connected in the electrical circuit are made a part thereof and substituted for the other elements when altered as aforesaid.

NICHOLAS DIPPEL. 

